For image generation using an ultrasound imaging apparatus, ultrasound probes are used. In recent years, for ultrasound probes, 2D array ultrasound transducers have been used. For the 2D array ultrasound transducers, the number of elements of piezoelectric transducers is substantially large. Therefore, wiring of connecting leads that connect elements (ultrasound transducers) to electronic circuits (delay circuit, etc.) causes a problem. That is, when the number of leads that are connected to the elements arranged two-dimensionally is substantially large (for example, 4096), while the overall size of an ultrasound transducer is small, it is difficult to ensure that there is space to establish wiring of the leads.
It is necessary to solve this type of wiring problem pertaining to connecting leads. In order to solve this problem, processing that adds signals from piezoelectric transducers by, for example, an electric circuit etc. is performed. By performing such processing, the number of leads that are wired between the piezoelectric transducers and the electronic circuits (delay circuit, etc.). Furthermore, arrangement of this circuit is also a problem. That is, because the further the distance between the piezoelectric transducers and the electronic circuits is, the longer the length of the leads is, not only the arrangement of the leads becomes difficult, but problems of cross talk or noise arise. These problems are desired to be solved.
For example, conventionally, an ultrasound transducer with the configuration in which integrated circuits (IC's) are disposed on surfaces in the opposite direction to the direction of ultrasonic radiation, and piezoelectric transducers and IC's are directly electrically connected is proposed (for example, U.S. Pat. No. 6,551,248). By applying this configuration, the problems of arrangement of wiring caused by the length of leads, and the problems of cross talk and noise can be solved. Meanwhile, in the explanation below, the surface of a piezoelectric transducer in the opposite direction to the direction of ultrasonic radiation may be described as the “rear surface”.
Moreover, conventionally, depending on a body region, ultrasound probes in various shapes have been used. When diagnosing the circulatory system, such as the heart, using an ultrasound imaging apparatus, an ultrasound probe is applied from the gap between the ribs. The ultrasound probe that is used in these cases is generally configured such that it has an ultrasound transducer in which the aperture of the ultrasonic radiation surface is small and in which the ultrasonic radiation surface is flat.
Moreover, in contrast, when diagnosing the digestive system, such as the liver, using the ultrasound imaging apparatus, the distance between the target diagnostic section and the body surface in subjects is relatively long. Moreover, when diagnosing the digestive system, the area of the target diagnostic section in subjects is relatively wide.
Furthermore, when diagnosing the diagnostic system, it is also necessary to discharge the gas inside the body of subjects, which adversely affects the ultrasonography in the ultrasonographic field.
The ultrasound probe that is used in these cases is generally configured such that it has an ultrasound transducer in which the aperture of the ultrasonic radiation surface is large and the ultrasonic radiation surface is formed in a curved shape having an arc shape, or a convex shape.
For the purpose of enlarging the aperture of the ultrasonic radiation surface of the ultrasound probe, it is difficult to make the respective size of the piezoelectric transducer in the ultrasound transducer large. That is, if the size of the piezoelectric transducer in the ultrasound transducer is made large, it may decrease the resolution capability; hence, there is a limitation on making the size of the piezoelectric transducer large. Therefore, when using an ultrasound probe having a large aperture, in order to make the ultrasonic radiation surface large, it is necessary to increase the number of piezoelectric transducers. However, that number is substantially large.
In an ultrasound probe, when the aperture of the ultrasonic radiation surface is large and when the ultrasonic radiation surface has a curved shape having an arc shape, or a convex shape, it is not easy to make the size of the IC's of the ultrasound transducer large, and moreover, the manufacturing cost is increased.
Therefore, when the aperture of the ultrasonic radiation surface is large and when the ultrasonic radiation surface has a curved shape having an arc shape, or a convex shape, it is difficult to dispose the IC's on the rear surface of the piezoelectric transducer as shown in U.S. Pat. No. 6,551,248. That is, it is not easy to dispose the IC's corresponding to the rear surface of the convex shaped or curve-shaped group of piezoelectric transducers in a high-density and space-saving manner.
Moreover, it is not easy to form the IC's having a shape corresponding to the rear surface of the convex shaped or curve-shaped group of piezoelectric transducers. Moreover, even if it is possible to provide or form these types of IC's, the manufacturing cost increases.
As described above, conventionally, depending on the number of the piezoelectric transducers or the arrangement pattern of the piezoelectric transducer, there have been various limitations and there have been cases in which it was difficult to set the IC's.